Dynamic eco-techno-economic analysis of low-carbon hydrogen production from methane

Hydrogen is currently produced predominantly through fossil fuel reforming, which accounts for approximately 3% of annual global CO₂ emissions. To reduce the carbon intensity of hydrogen production, several low-carbon alternatives have been proposed, including biogas reforming and electrified steam methane reforming (e-SMR). Biogas benefits from its biogenic origin, leading to near net-zero carbon emissions, while e-SMR replaces the natural gas combustion used for reactor heating in conventional SMR with electrical heating. This modeling study performs a dynamic techno-economic assessment of these processes in comparison with state-of-the-art steam methane reforming (SMR) and auto-thermal reforming (ATR), evaluating the impact of implementing carbon capture and permanent storage (CCS). The analysis incorporates time-resolved and seasonal variations of real electricity prices in French, Swiss and German scenarios, employed as reference cases for low and high electricity grid footprints. Large-scale SMR and ATR plants exhibit the highest process efficiency (79-81%), which remains stable when CCS is implemented (77-81%). Lower efficiencies are observed for biogas reforming (56-67% with base case and 65-69% with CCS) and e-SMR (59% with base case and 71% with CCS) due to their smaller scale and the presence of CO₂ in the feed. CCS significantly reduces carbon footprints: from 8.6-8.7 to 1.2-3.4 kg_CO2 kg_H2 ^-1 for SMR and ATR and from 0.2-1.0 to -10 to -4 kg_CO2 kg_H2 ^-1 for biogas reforming. e-SMR emissions (from 6-18 to 0.3-10 kg_CO2 kg_H2 ^-1 with CCS) depend strongly on the electricity mix. The possible presence of carbon credits makes the application of CCS economically beneficial for SMR and ATR (H₂ cost ranging from 1.6 to 1.3 € per kg_H2 ) and for biogas reforming (from 3.7 to 3.5 € per kg_H2 ). e-SMR competitiveness is highly electricity-price-dependent and benefits from CCS regardless of carbon credits, performing best in France (3.7 to 2.6 € per kg_H2 with CCS) and worst in Switzerland (4.2 to 3.1 € per kg_H2 with CCS). Intermittent operation to exploit low-cost electricity may further reduce e-SMR costs by 0.1-0.4 € per kg_H2 .